Bowlby's theory of child-parent attachment predicts that children who develop a secure relationship with their mother, compared to children who become insecurely attached to their mother, will have less difficulty establishing harmonious relationships with nonfamily members. Although a number of studies have shown that securely attached children are more socially competent around peers, no studies have examined links between mother-child attachment and the ability to form new peer relationships. In addition, in previous studies of attachment and peer interaction investigators have utilized global measures of positive and negative behaviors rather than looking at the particular social processes hypothesized to be important to peer relationships. The distinctive feature of this application is that it draws upon both Bowlby's theory of attachment and Gottman's theory of friendship formation to describe more precisely the associations between attachment security and peer relationships. More specifically, this application: 1) Tests the hypothesis that securely attached children progress more quickly toward friendship with a peer; 2) Provides a theoretically driven analysis of securely and insecurely attached children's friendship formation skills; 3) Tests the hypothesis that securely attached children elicit more positive behavior from peers as well as directing more positive behavior towards peers; 4) Examines whether a third variable, parental management of peer contacts, explains any obtained associations between attachment and friendship formation. These aims will be achieved by studying friendship formation in previously unacquainted pairs of 3-4 year-old children. Attachment security will be measured with the Attachment Q-set. Progression toward friendship will be indexed by behavioral coding of children's interactions, child mood assessment, and maternal report. Parental management of peer contacts will be assessed via phone interviews with parents. Relationships are dyadic in nature, with the relationship history of each participant influencing the relationship. For this reason the association between attachment and friendship formation will be studied by comparing dyads in which both children are securely attached to dyads in which one child is securely attached and the other insecurely attached to mother. The results aid in understanding how parent-child relationships influence the formation of new social bonds.